Information can be shared between computing devices by a variety of techniques. For example, a first computing device displays a bar code and another computing device reads the bar code. The first computing device may insert information to be shared into the bar code and then display the bar code. The second computing device uses a bar code reading device to read the bar code and extract the information from the bar code. The two computing devices may be mobile devices in which case bar code sharing may likely occur in public places where unintended recipients can easily intercept the displayed bar code with their computing devices. Therefore, without security measures, the information may be compromised.